The case against SCART:
1.) Connector quality varies wildly. It's a big fat plug with 21 pins, when you only really need 6 for RGBs + stereo sound. Some connectors on equipment will snuggly hold the SCART cable ends, while others let it practically fall out at the slightly bit of tension.
2.) Cable quality varies wildly. It's not like everyone is just using it because "well, we've got this big massive back stock of quality SCART cables from the 90's. We might as well just use those instead of trying to make a new kind of cable". It seems like officially licensed cables are hard to come by (at least when shopping from the US), old 3rd party cables are a crap shoot on quality, and seemingly most quality SCART cables are ones made by hobbyists and niche ebay sellers. Other than maybe the reputation of a few good sellers, you never know if you're going to get some crap cable with the thickness of a telephone cord with virtually no shielding that causes audio to buzz like crazy at the least.
3.) SCART AV switch quality varies wildly. When you're hunting down a SCART switch for all your retro consoles outputting RGB over SCART, it seems to be mostly a giant gamble. There's maybe 1 or 2 that sound like they're good quality that were recently made by hobbyists (I forget the names, but I've seen posts about them here) but I think I recall them being kinda pricey too. If you're trying to get SCART switches from back-in-the-day it seems like either the quality is horrible with signal bleed or other issues, supposed good quality brand ones are very hard to find, and/or they just don't have very many ports.
4.) Professional and 'prosumer' equipment (mostly) don't use SCART. A lot of the enthusiasts seem to want high quality equipment whether it be a professional CRT display or fancy upscaling equipment to play on a HDTV. PVMs, BVMs, and other professional CRT displays seem to mostly use BNC connectors while some other oddballs might use some other non-SCART ports. AV switches that can handle RGB and have many ports generally don't have SCART ports either. If you can find a consumer AV switch with a lot of ports it's going to be RCA jacks and meant for component, while professional switches will probably use BNC. The Framemeister uses whatever custom port that is that will need an adapter. Maybe there's another random device or two I'm not thinking of, but the OSSC is the only 'upscaler' (I know it's not an upscaler by definition) that has SCART. I assume this is because of the current SCART trend, and because it comes from Europe
.So basically, it seems like most equipment you'd be using (except for consumer European CRTs) is either going to be BNC or some not widely used connector that you're going to need an adapter for regardless. I personally adapted all my retro stuff to RCA jacks so that I can just use standard RCA cables, then it just takes simple RCA-to-BNC adapters to hook to stuff such as a BVM or Extron Crosspoint switch. I'm not an expert cable maker, so I ended up making RCA break-out boxes for RGB on each retro console (before I got my Extron switch), but I'm sure people who are making cables all the time could make say just a straight up SNES RGB RCA cable.
